Diversity of HLA class I and class II alleles in Iran populations: Systematic review and Meta-Analaysis

Abstract

The human leukocyte antigen (HLA) system plays an essential role in the peptides antigen presentation and more regulation of immune responses. Regarding all HLA molecules' associations with various diseases and their clinical utilities in understanding drug reactions or prediction of transplantation outcome, there is a need for much more extensive HLA data generated from Asian countries. Method: A comprehensive search was conducted in electronic databases between 1990 and 2021 to identify relevant articles to HLA frequency in the normal Iranian population. Two independent reviewers screened and selected the eligible studies. After data extraction, the meta-analysis was performed using STATA version 14. The overall frequencies and their 95 confidence intervals (CIs) were obtained using the random-effects model. Results: Among 1141 studies 78 were eligible for this study and the sample sizes varied from 14 to 15,600. The most frequent alleles of HLA class I were HLA-A*02 (22; 95CI: 20-24; I-2 = 88.63), -B*35 (18; 95CI: 16-21; I-2 = 90.95), -C*12 (18; 95CI: 13-22; I-2 = 89.51). HLA-DQA1*01 (42; 95CI: 40-44; I-2 = 56.80), -DQB1*03 (38; 95CI: 35-42; I-2 = 92.38), and -DRB1*11 (24; 95CI: 22-26; I-2 = 90.72) were the most frequent alleles of HLA class II in Iran. Discussion: Our meta-analysis results point out that the comprehensive report of HLA allele frequency in the Iranian population could be helpful as reference data for planning and managing transplantation and immune disease treatment in Iran.